Vol. 13 Issue 1
M.A. Al-Gwaiz and V. Anandam
The representation of a harmonic function outside a compact set in IR^n is obtained, subject to one-sided growth condition at infinity. By an inversion transformation, this result is used to characterize the behavior of a harmonic function in the neighbourhood of an isolated singular point, and leads to a generalized version of Bocher's theorem
Riyad Y. Hamzah and Nabil M. El-Torkey
The aromatic amines including o-toluidine, 4-chloro-o-toulidine, 4-4'-methylene dianiline (MDA), 4, 4'-methylene bis (2- chloroaniline) (MOCA) and its three possible substitutes, ethacure 300, cyanacure, and polacure 740 M, were used to determine the mutagenic activities in Salmonella typhimurium strains TA98 and TA100. The mutagenic activities of these chemicals were compared with their effects on ethoxyresorufin o-deethylase (EROD) activity and aldrin epoxidase (AE) activity in rat liver. The chemicals o-toluidine, 4-chloro-o-toluidine, MDA, MOCA and its substitutes, ethacure 300 and cyanacure, showed mutagenic activities, while polacure 740 M showed no mutagenic activity. All the mutagens caused an increase in EROD activity, while polacure 740 M showed no appreciable increase in EROD activity. Thus, there was excellent correlation between mutagenicity and EROD induction. This supports the conclusion that the ability of a chemical to induce EROD bears some relationship to its carcinogenic potential.
S.H. Al-Khowaiter
The use of 6% Ni/Al2O3 catalyst for the hydrodealkylation of toluene (THD) using the pulse technique at differential reactor conditions has been investigated. The hydrodealkylation selectivity (or the selectivity to benzene production) was optimum at 593 K showing some hydrogenation of the aromatic ring at lower temperatures and favoring hydrocracking at higher temperatures. Activation energy was found to be 97.9 kJ/mol. Reaction rates at low conversions runs were interpreted both by empirical power equation of the type r= KPTmPnH and by Langmuir-Hinshelwood type equations, determining the corresponding parameters. A good fit to the experimental results was obtained with the empirical equation (m=0.65; n=0.16) and the L-H equation of the form:
r=4.104 PTPH^1/2 /(1+0.037 PT + 0.086PH^1/2)^2
A reaction sequence is presented for the rate determining surface reaction suggesting sequential reactant absorption at a common catalytic site for toluene and atomic hydrogen.
S.H. Al-Khowaiter
The use of 6% Ni/Al2O3 catalyst for the hydrodealkylation of toluene (THD) using the pulse technique at differential reactor conditions has been investigated. The hydrodealkylation selectivity (or the selectivity to benzene production) was optimum at 593 K showing some hydrogenation of the aromatic ring at lower temperatures and favoring hydrocracking at higher temperatures. Activation energy was found to be 97.9 kJ/mol. Reaction rates at low conversions runs were interpreted both by empirical power equation of the type r= KPTmPnH and by Langmuir-Hinshelwood type equations, determining the corresponding parameters. A good fit to the experimental results was obtained with the empirical equation (m=0.65; n=0.16) and the L-H equation of the form:
r=4.104 PTPH^1/2 /(1+0.037 PT + 0.086PH^1/2)^2
A reaction sequence is presented for the rate determining surface reaction suggesting sequential reactant absorption at a common catalytic site for toluene and atomic hydrogen.
S.H. Al-Khowaiter
The use of 6% Ni/Al2O3 catalyst for the hydrodealkylation of toluene (THD) using the pulse technique at differential reactor conditions has been investigated. The hydrodealkylation selectivity (or the selectivity to benzene production) was optimum at 593 K showing some hydrogenation of the aromatic ring at lower temperatures and favoring hydrocracking at higher temperatures. Activation energy was found to be 97.9 kJ/mol. Reaction rates at low conversions runs were interpreted both by empirical power equation of the type r= KPTmPnH and by Langmuir-Hinshelwood type equations, determining the corresponding parameters. A good fit to the experimental results was obtained with the empirical equation (m=0.65; n=0.16) and the L-H equation of the form:
r=4.104 PTPH^1/2 /(1+0.037 PT + 0.086PH^1/2)^2
A reaction sequence is presented for the rate determining surface reaction suggesting sequential reactant absorption at a common catalytic site for toluene and atomic hydrogen.
Abdel- Aal M. Abdel-Karim and Sayed A. Azzaz
The dyke swarms in Sinai are important in understanding late Precambrian activity in the northern Arabian-Nubian Shield. Fieldwork and K-Ar age dating indicate that these dyke swarms can be described in terms of two major members.
(1) The old (mafic) dykes, mainly consisting of basalts and andesites, which, with minor lamprophyres and plagiophyres , range in age rom 586-563 Ma giving a mean age of 574 Ma. They are distinguishable from older 586-577 Ma basalts with a mean of 581 Ma; and younger 570-563 Ma andesites with a mean of 567 Ma. The old dykes crosscut the basement rocks except the Younger granites.
(2) The young (felsic) dykes, comprising dacites-to-rhyolites and quartz porphyries and range in age from 545-536 Ma with a mean of 541 Ma. They crosscut almost all the basement rocks, the exception being the Younger Granites phase-III.
All the former basement rocks, together with the old and young dyke swarms, are cut by 517-502 Ma (509 Ma mean) late basalt dykes.
These data represent the age of old dykes emplacement and cooling, and place a minimum age of the young dykes probably due to the loss of argon attributable to the influence of the post-extrusion deformation.
Saleh A. Al-Hassoun and Abdullah M. Albrahim
A relatively simple procedure to predict the base flow component of stream flow in a watershed is presented. This base flow depends upon the aquifer recharge, the initial state of water table elevations and the fluctuations in river stage. The methodology consists of deriving analytical solutions to the linearized one-dimensional Boussinesq equation for groundwater flow. The developed methodology was verified using a selected watershed and a good agreement was obtained between observed and computed results. An illustrative numerical example is given.
H.I. Abdel- Gawad
The diffraction of an acoustic wave from a point source of sound by an absorbing half-place and a nearly half plane (y= εg (x,z); x ≤ 0 and 0 ≤ ε << 1) in the presence of a moving fluid is studied. This is done by using a recently developed method. It is assumed throughout the paper that the point source sets in at time t=0. When ε=0, it is shown that the far field of the diffracted wave is anharmonic. It behaves merely as the inverse of the distance from the point source but as if the point source movies at the fluidspeed far from the barrier. On the other hand, it is found that acoustic noise reduction by a nearly half-plane barriers y= εg (x,z); 0≤ g (x,z) ≤ 1; x ≤ 0 and -∞ < z < ∞ is better than reduction by a half-plane one.
Ali A.Al-Jaloud, Mohammed Rafi and Isam Bashour
Fractionation of micronutrients into 5 fractions was carried out on ten selected soils in Saudi Arabia (Tessier et al 1979). The ranges for different micronutrient fractions were: 0- 796,0-105, 0- 75 amd 0- 59942 ug/g for Mn, Zn, Cu and Fe, respectively. The residual fraction constitutes the absolute majority of all fractions and the order of the 5 fractions was: Residual > Fe-Mn Oxide bound > CO3 bound> organic bound> exchangeable.
The DTPA extractable micronutrients ranged from 1.56- 16.30 ug/g for Mn, 0.09- 2.20 ug/g for Zn, 1.51-17.7 ug/g for Fe and 0.07- 2.73 ug/g for Cu extraction of micronutrients with DTPA showed strong relationship with micronutrients estimated by using different fractionation schemes. Therefore, it is considered a good estimation for the availability of micronutrients in the studied soils.
Hussein M. Abo-Ghobar and Fawzi Said Mohammad
Three identical drainage type lysimeters, 2x2x1 m in size, were installed at the Educational Farm of the College of Agriculture, King Saud University and planted with alfalfa to obtain reference crop evapotranspiration. The measured evapotranspiration was correlated with the evapotranspiration estimated from the Penman and Jensen- Haise methods using meteorological data from Dirab. The straight line correlation with intercept was not found to be significantly high under the local arid climatic conditions. A better correlation was obtained using a straight line correlation passing through the origin. The highest coefficient of correlation (R^2= 0.97) was obtained between the measured evapotranspiration from alfalfa and the evaporation from class A pan